1. Field of the Invention
Embodiments of the present invention generally relate to a user-adjustable spring for use in a shock absorber.
2. Description of the Related Art
Integrated damper/spring vehicle shock absorbers often include a damper body surrounded by a mechanical spring. The damper often consists of a piston and shaft telescopically mounted in a fluid filled cylinder. The mechanical spring may be a helically wound spring that surrounds the damper body. Various integrated shock absorber configurations are described in U.S. Pat. Nos. 5,044,614; 5,803,443; 5,553,836; and 7,293,764; each of which is herein incorporated, in its entirety, by reference.
The spring mechanism of many shock absorbers is adjustable so that it can be preset to varying initial states of compression. In that way the shock absorber can be adjusted to accommodate heavier or lighter carried weight, or greater or lesser anticipated impact loads. In motorcycle racing, particularly off-road racing, shock absorbers may be adjusted according to certain rider preferences.
U.S. Pat. No. 5,044,614 (“the '614 patent”) shows a damper body carrying a thread 42. A helical spring 18 surrounds the damper body where the two form an integrated shock absorber. The compression in the helical spring 18 may be pre-set by means of a nut 48 and a lock nut 50. Because the nut 48 and lock nut 50 must be relatively torqued to prevent nut 50 rotation upon final adjustment, the shock absorber must typically be removed from its vehicle in order to allow torquing wrench access. Once the spring 18 is in a desired state of compression, lock nut 50 is rotated, using a wrench, up against nut 48 and tightened in a binding relation therewith.
The system described in the '614 patent requires that the user be able to access a large amount of the circumference of the shock absorber, and specifically the nut 48 and lock nut 50, with a wrench (e.g. col. 4, lines 15-17). Unfortunately many shock absorbers, as mounted on a corresponding vehicle, are fairly inaccessible, and have limited surrounding wrench space because of other surrounding vehicle hardware and/or, as in the instant case, a separate damping fluid reservoir or “piggyback.” What is needed is a shock absorber having a spring that can be readily adjusted while the shock absorber is mounted on a vehicle. What is needed is a motorcycle “monoshock” having a spring that can be easily adjusted without removing the shock from the motorcycle. What is needed is a shock absorber having a spring where the state of spring adjustment is constantly indicated and easily visible while the shock is mounted on a vehicle.